Because they are easier to obtain (i.e. you don't need a script from the doctor to get them, you can go and buy them freely) and in some cases can give you the same high as street and prescription drugs
<span>The question is asking us to choose, from a list, which activity can substantially increase the activity level of a person lifestyle. The activity here is the physical activity, so the question is, which of the following would make you most physically active. The answer is walking to school - here you would be using your muscles to move. When you are driving a car or using an escalator, you are using technology to move so you don't have to use physical strength.</span><span />
Maybe give mee the full question so I could see
The muscular system<span> is responsible for the movement of the human body. Attached to the bones of the </span>skeletal system<span> are about 700 named </span>muscles<span> that make up roughly half of a person's body weight. Each of these </span>muscles<span> is a discrete organ constructed of </span>skeletal muscle<span> tissue, blood vessels, tendons, and nerves.</span>